Description
int 
jdtounix ( int jday )
     This function will return a Unix timestamp corresponding to the
     Julian Day given in jday or FALSE if
     jday is not inside the Unix epoch
     (Gregorian years between 1970 and 2037 or 2440588 <=
     jday <= 2465342 ). The time returned is
     localtime (and not GMT).
    
     See also unixtojd().